The present invention relates to apparatus in such pneumatic cylinders, "Origa Cylinders", where the piston is provided with a laterally directed dog projecting through a slit in the cylinder wall, the dog moving along the slit under the action of the pneumatic pressure acting on the piston. The slit is closed off and sealed towards the interior of the cylinder with the aid of a sealing strip.
The function of such cylinders can be regarded as well-proven and satisfactory. However, there is a disadvantage in that due to its design the dog extends out through a relatively narrow slit, resulting in that the apparatus can only take up limited skew loads, i.e. forces with components transverse the direction of movement of the dog. Attempts have been made to solve these problems and provide the apparatus with greater ability to take up forces by mounting different forms of support rails on either side of the slit. This has been found to be less suitable, however, due to the sides of the slit moving in relation to each other in response to the excess pressure inside the cylinder. This means that the support surfaces also move in relation to each other. Another solution uses a guide attached along the side of the cylinder and with a width corresponding to the cylinder diameter. The two opposing long sides of the guide are prismatically shaped and guide a runner moving on the guide, this runner being used to attach the components which are to be driven by the apparatus. The dog is attached to one side edge of the runner. Due to its design, this apparatus will be relatively voluminous, and the force from the piston is to be transmitted via the dog to the runner, which constitutes the part taking up force. This further means that the piston itself is subjected to skew loads, even for purely axial loading moments, due to the moment caused by the design.